Electrical PPT

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• CanSat Is a Simulation of a Real Satellite • It Performs a Mission and Collects Data • Typical Missions Can Be Atmospheric Measurements, Video • Capture, Picture Taking, Communications, or Navigation • The Missions Can Be Simple or Complex • The Only Requirement Is that the Mission Must Fit in a Twelve Ounce Soda Can • This Program will introduce you to How CanSat is Built • It Includes most subsystems found in Satellites

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• CanSat Shall Be Built to Fit in a Standard Soda Can– • Diameter Is 130+/- 2 mm • Weight is usually less than 700 gms. • No Parts of the CanSat Shall Extend Beyond the Surface of the Soda Can Until Deployed • CanSat Shall Operate off of Battery or Solar Power • CanSat Can Use Communications(usually RF communications) – Antennas Should Be Flexible. • A Parachute Shall Be Properly Secured to One End of the CanSat.

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• CanSat Is Launched on a HighPowered Model Rocket – The Rocket Is 4” in Diameter and About 7’ Tall – Capable of Reaching Over a Mile in Altitude – CanSat Is Stowed in the Upper Airframe Below the Nose Cone • The Rocket Is Launched and When It Reaches Apogee, the Rocket Breaks Apart to Eject the Main Parachute – This Causes the Upper Portion of the Rocket to Point Down • The Nose Cone Will Fall Out and the CanSat Will Fall Afterwards • The Parachute Brings the CanSat Gently Back to Earth 5

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• “Satellite is an object which has been placed into orbit by human endeavor” Wikipedia • “An artificial body placed in orbit round the earth or another planet in order to collect information or for communication” – Oxford Dictionary • Various Definitions for satellites have been given. • Main concepts for the satellite – • Orbit around the planet. • Collects information for sending back to ground station.

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• A Satellite Is Made Up of Six Major Subsystems: • Power Subsystem • Data Handling Unit/Ground Control Systems • Communications Subsystem • Sensor Payload or Subsystems • Structure • Attitude Control Subsystem • Following slides will explain each subsystem in larger detail and will use as reference

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• The Power Subsystem Provides Electrical Power to the Satellite. Usually, this is provided using solar panels. • Solar Panels Are Comprised of Solar Cells, i.e., Semiconductor Devices Called Photovoltaic. • Designers Select the Types of Solar Cells to Meet Their Power Requirements, Budget, Mass and Size. • Various types of Batteries used in the power system are – • Ni-Cd. • NiH2 • Li-Ion. • The main precautions required in the design of the power system is the fault detection unit.

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• The Data Handling Unit (DHU) Is a Computer That Controls the Flow of Data and Instructions. – It Controls Payloads and Collects Data From the Payloads – It Accepts Commands Received by the Communications System and Sends Data to the Communications System for Transmission to the Ground Station – It Is the Brains of the Satellite.

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• The satellite usually contains a radio receiver for transmitting data to the ground system and receiving commands from the ground station. • The Spacecraft Has a Transmitter Used to Send Telemetry (i.e., the Name for Data Sent or “Down-Linked” From the Spacecraft).

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• Payloads on a Satellite Are Generally Some Type of Sensor • It Can Be a Radio Receiver Designed to Detect Certain types of Signals • It Can Be a Camera Used to Take Pictures of the Earth in Various Light Spectrums. • It Can Be Radiation Detectors, or Any Type of Sensor to Detect Something. • The sensors are responsible for the navigation and control system.

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• The structure of satellite is generally made of Al or other light-weight material. • Attitude Control Systems Allow the Orientation of the Spacecraft to Be Controlled.

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•Time Limit: 45 minutes

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Electrical Subsystem

Mechanical Design

Software Analysis 16

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Kill switch/signal Buzzer(5V)

GPS(3.3V)

Motor Driver(3.3V)

5V CanSat Batteries

9V

Voltage Measurement Hardware(9V)

9V

Arduino (9V) 5V

9V

on/off Motor(9V)

Motor Driver(5V)

3.3 V SD card(3.3V)

P&T Sensor(3.3V)

Radio Transceiver(3.3V

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• The power budget is the allocation of power to be consumed by the components of the system. • This requires the analysis of the power requirement of each of the components and is an integral part of the design of the power system. • This is required to determine the distribution of power and total power required in the system.

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• The Antenna selection is done on the basis on Link Budget. • Link Budget equation –

PRX = PTX + GTX + GRX – LTX – LRX – 20log(4πd/λ) • • • •

P: Power G: Gain L: loss in transmission or receiver The last term accounts for channel loss

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BMP 085 (T&P sensor) Sampling rate: 50 KHz

Buzzer

Gather Data Transmit Data to Ground

Read GPS Data

GPS Data (Sampling Rate: 1 Hz)

Impact Measurement

MMA 7361 (Accelerometer) (Sampling rate: 100 Hz)

after payload has landed

SD Card

FSW written on Arduino Nano (Payload)

Xbee Radio ‘START’ to activate telemetry Data Read

Battery Voltage

Electromechanical Deployment Mechanism + Aerobraking structure 20

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• The Communications Subsystem Is a Transmitter Radio Used to transmit telemetry Which Is the Data Collected in the CanSat. • This system allow the CanSat to send the data back to the Ground Station that can process the data to get relevant information. • This is one of the most critical parts of the CanSat design that requires the knowledge of the CanSat, the Ground System as well as the channel. • The following are the selection criterion: • Gain • Range • Frequency • Price

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• The micro-controller is the main data handling unit for the CanSat. • We are using an Arduino as the microcontroller unit for the CanSat. • The selection is done considering the following outlined requirements: Arduino Uno

Arduino Mega 2560

Arduino Nano

Processor Speed(MHz)

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16

16

Operating Voltage

5

5

5

Data Interface (D/A)

14/6

54/16

14/8

Size(cm x cm)

6.5x5.2

10.1x5.2

4.3x1.85

Flash Memory(kB)

32

128

32

Price(in USD)

25

65

50

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Factors affecting sensor selection for a CanSat system: (in priority order) 1) 2) 3) 4) 5)

According to the desired operation Operating Frequency, accuracy, sensitivity, range of operation Data interface required Power Consumption Weight, cost and dimensions

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